This paper was prepared for the SPE-European Spring Meeting 1974 of the Society of Petroleum Engineers of AIME, held in Amsterdam, the Netherlands, May 29–30, 1974. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Netherland Section of the Society of Petroleum Engineers, P. O. Box 228, The Hague, the Netherlands. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract In the interference problem some aspects which have not yet been taken in consideration were examined in this paper. These problems are:How could paper. These problems are:How could the turbulence influence gas well interference tests, andrelationship between producing wells and their distribution. In the first part of this work it was shown that turbulent flow is influencing the transient behaviour during well interference test, and a method of evaluation was indicated. A calculation example has shown quantitatively the importance of neglecting turbulence effect in interference evaluation. In the second part of the paper the relationship between number paper the relationship between number of producing wells and single well rate as affected by well interference was discussed. The interference concept is usually associated with the idea that an increased number of wells reduces the single well rate or, for maintenance of a constant rate, requires a higher pressure draw-down. It is demonstrated pressure draw-down. It is demonstrated that this conclusion is valid only if the hydrocarbon reserve is in direct contact with an efficient lateral water zone and if the wells are non-uniformly distributed over the structure.